🛡️ CVE-2025-39983 — kernel

🟠 CVSS 8.8 — High ✅ No Known Exploit NVD
8.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue

This fixes the following UAF caused by not properly locking hdev when

processing HCI_EV_NUM_COMP_PKTS:

BUG: KASAN: slab-use-after-free in hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036

Read of size 4 at addr ffff8880740f0940 by task kworker/u11:0/54

CPU: 1 UID: 0 PID: 54 Comm: kworker/u11:0 Not tainted 6.16.0-rc7 #3 PREEMPT(full)

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014

Workqueue: hci1 hci_rx_work

Call Trace:

<TASK>

dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120

print_address_description mm/kasan/report.c:378 [inline]

print_report+0xca/0x230 mm/kasan/report.c:480

kasan_report+0x118/0x150 mm/kasan/report.c:593

hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036

hci_num_comp_pkts_evt+0x1c8/0xa50 net/bluetooth/hci_event.c:4404

hci_event_func net/bluetooth/hci_event.c:7477 [inline]

hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531

hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070

process_one_work kernel/workqueue.c:3238 [inline]

process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321

worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402

kthread+0x70e/0x8a0 kernel/kthread.c:464

ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148

ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

</TASK>

Allocated by task 54:

kasan_save_stack mm/kasan/common.c:47 [inline]

kasan_save_track+0x3e/0x80 mm/kasan/common.c:68

poison_kmalloc_redzone mm/kasan/common.c:377 [inline]

__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394

kasan_kmalloc include/linux/kasan.h:260 [inline]

__kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359

kmalloc_noprof include/linux/slab.h:905 [inline]

kzalloc_noprof include/linux/slab.h:1039 [inline]

__hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939

le_conn_complete_evt+0x3d6/0x1220 net/bluetooth/hci_event.c:5628

hci_le_enh_conn_complete_evt+0x189/0x470 net/bluetooth/hci_event.c:5794

hci_event_func net/bluetooth/hci_event.c:7474 [inline]

hci_event_packet+0x78c/0x1200 net/bluetooth/hci_event.c:7531

hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070

process_one_work kernel/workqueue.c:3238 [inline]

process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321

worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402

kthread+0x70e/0x8a0 kernel/kthread.c:464

ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148

ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Freed by task 9572:

kasan_save_stack mm/kasan/common.c:47 [inline]

kasan_save_track+0x3e/0x80 mm/kasan/common.c:68

kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576

poison_slab_object mm/kasan/common.c:247 [inline]

__kasan_slab_free+0x62/0x70 mm/kasan/common.c:264

kasan_slab_free include/linux/kasan.h:233 [inline]

slab_free_hook mm/slub.c:2381 [inline]

slab_free mm/slub.c:4643 [inline]

kfree+0x18e/0x440 mm/slub.c:4842

device_release+0x9c/0x1c0

kobject_cleanup lib/kobject.c:689 [inline]

kobject_release lib/kobject.c:720 [inline]

kref_put include/linux/kref.h:65 [inline]

kobject_put+0x22b/0x480 lib/kobject.c:737

hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]

hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173

hci_abort_conn_sync+0x5d1/0xdf0 net/bluetooth/hci_sync.c:5689

hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332

process_one_work kernel/workqueue.c:3238 [inline]

process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321

worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402

kthread+0x70e/0x8a0 kernel/kthread.c:464

ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148

ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

How this vulnerability can be exploited

This issue can be reached from an adjacent network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

CVE-2025-39983 is recorded against 2 packages.

  • kernel (from 6.15.0 up to 6.16.10)
  • unknown

Timeline and source

Published on 15 October 2025 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2025-39983 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity High
CVSS Score 8.8
CVSS Vector CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-10-15
Updated 2026-08-12
Modified 2026-08-06
Fix URL N/A

Affected Packages

Software From version Fixed in
kernel 6.15.0 6.16.10
unknown

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